Note that the 3D mode is not available on the iPhone 3G or the 2nd generation (2008) iPod touch.
Road maps at 1:1,000,000 and 1:250,000 for all of England, Scotland and Wales are built in to the app:
Northern Ireland is not included, nor are the Channel Islands. The Isle of Man is included at 1:1,000,000 and 1:250,000 only.
To download detailed maps, in 2D mode touch the screen until a blue square appears and then sweep out the area to download. The maps are installed in 5km x 5km tiles. You can download either 1:25,000 maps or both 1:25,000 and 1:10,000 maps.
Once downloaded the maps are retained until you delete them, so you can use the app with no network connection. If it seems nothing has happened after downloading, zoom in more.
The 1:25,000 maps are similar in detail to paper 1:50,000 Landranger® maps; they're not quite as good as the 1:25,000 paper Explorer® maps because they don't show field boundaries and a few other details. They do show contour lines, and they now show footpaths based on data from OpenStreetMap.org.
The 1:10,000 maps show street names and building outlines; they are ideal for urban navigation.
At the maximum zoom, one pixel on the screen represents one metre on the ground. Coverage at this level of detail is available over the entire country.
You can now also view the maps in 3D: 3D mode is not available on the iPhone 3G or the 2nd generation (2008) iPod touch.
In 3D mode, use normal one-finger gestures to go N, S, E and W. To turn, pitch up and down, and change altitude, use the sliders at the sides of the screen. (You can also pinch and un-pinch to zoom in and out, but in 3D mode it's normally better to move closer rather than zooming in.)
Hint: you can often make the app more responsive by tilting your view down so that the horizon is not visible; there is a lot of map content squashed up near the horizon.
The buttons at the bottom of the screen can be shown by touching the small arrow button at the bottom left. The magnifier button shows the search screen. This searches a national gazetteer of place names, streets and postcodes. This data is stored on the device; no network connection is needed to search.
Touch a search result in the listing to go to that feature on the map.
The button to the right of the search box toggles between national search and local search modes. When you change to local search mode, only the currently-visible area is searched; this is shown by a black outline if you zoom out.
The layout of the screen changes in portrait and landscape orientations. In portrait mode you can temporarily hide the search results list to interact with the map by touching the arrow button to the right of the tabs. You can limit the search to a rectangular area by touching the button to the right of the search box; this is useful when searching for a very common name.
To show your location, touch the satellite button at the bottom left of the screen. Your position is shown by a blue spot, and the circle around it shows the estimated accuracy. The panel at the bottom of the screen shows the reported accuracy and altitude. Turn on the Lock button to keep the map centred on your location.
If your device has a compass, a compass button is shown; this rotates the map to align with the ground.
Touch the arrow button at the top right to show the co-ordinates display. This shows the grid reference, or latitude-longitude co-ordinates, of the point under the crosshairs at the centre of the screen (which is not necessarily your current position). It also shows the altitude at this point; the altitude data is approximate. To enter a grid reference or other co-ordinates, touch the keyboard button to the left of the co-ordinate display.
Touch the "gears" button to show the settings panel. Here you can adjust the slope shading and height tint effects, including the simulated sunlight direction. For urban areas you might prefer to turn this off as it makes the app slightly quicker.
Also in the settings panel you can adjust the point at which the app fades from one map scale to the next. Above, the transition from 1:25,000 to 1:250,000 is visible.
Hint: the app can be more responsive if you avoid zoom levels where a fade is in progress.
You can change the units used for the scale and coordinates display. The scale can be in km or miles, and coordinates can be shown as an OS grid reference or as Latitude-Longitude in either WGS84 or OSGB36 datum, either in decimal degrees, degrees and minutes, or degrees minutes and seconds.
In 2D mode, the "maps" button shows where detailed maps have been installed. Green indicates 1:25,000 maps and yellow indicates 1:10,000 maps.
Zooming in when this overlay is active shows additional information about each 5km tile. You can also see overal statistics about your tiles at the bottom of the screen.
To delete maps, touch the delete button and then select an area in the same way as when installing.
UK Map is now available from Apple®'s App Store in the Navigation category for only £7.99.